• Title/Summary/Keyword: Nuclear Education

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A Nuclear Event Detectors Fabrication and Verification for Detection of a Transient Radiation (과도방사선 검출을 위한 핵폭발 검출기 제작 및 검증)

  • Jeong, Sang-Hun;Lee, Seung-Min;Lee, Nam-Ho;Kim, Ha-Chul;Cho, Seong-Ik
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.62 no.5
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    • pp.639-642
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    • 2013
  • In this paper, proposed NED(nuclear event detectors) for detection of a transient radiation. Nuclear event detector was blocked of power temporary for defence of critical damage at a electric device when a induced transient radiation. Conventional NED consist of BJT, resistors and capacitors. The NED supply voltage of 5V and MCM(Multi Chip Module) structures. The proposed NED were designed for low supply voltage using 0.18um CMOS process. The response time of proposed NED was 34.8ns. In addition, pulse radiation experiments using a electron beam accelerator, the output signal has occurred.

Radionuclides in Environmental Samples and Sample Concentration of Land in the Analysis in the Method of Direct (직접법에서 환경시료중 육상시료의 방사성 핵종 및 농도 분석)

  • Jang, Eun-Sung;Kim, Jin-Seop
    • Journal of Environmental Science International
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    • v.24 no.3
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    • pp.275-280
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    • 2015
  • In order to measure the Radionuclides and Concentration, the directly grinded land samples (river soil, pine leaves and mugwort) among the environment samples around the nuclear power plant were filled in a 450 mL Marinelli beaker and weighed to obtain the dry mass ratio of the samples. Then the background and land samples were measured for 80,000 sec. The analysis of the collected land samples showed that most of them contained less radiation nuclide than the detection minimum limit in the 'Ministry of Education, Science and Technology Public Notice No. 2010-32.'In others, the natural radionuclides $^{40}K$ were detected. Of the products of nuclear reaction discharged by a nuclear reaction, $^{134}Cs$ and $^{137}Cs$ are more easily detected, and their discharge sources can be traced using the relative ratio. Although the radioactive concentration in the vicinity of Kori Nuclear Power Plant, which is more than 1,100km away from Fukushima, the Japanese nuclear accident site, continuous monitoring is needed as the radionuclides can still be accumulated in the soil or animals and plants.

MULTI-SCALE MODELS AND SIMULATIONS OF NUCLEAR FUELS

  • Stan, Marius
    • Nuclear Engineering and Technology
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    • v.41 no.1
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    • pp.39-52
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    • 2009
  • Theory-based models and high performance simulations are briefly reviewed starting with atomistic methods, such as Electronic Structure calculations, Molecular Dynamics, and Monte Carlo, continuing with meso-scale methods, such as Dislocation Dynamics and Phase Field, and ending with continuum methods that include Finite Element and Finite Volume. Special attention is paid to relating thermo-mechanical and chemical properties of the fuel to reactor parameters. By inserting atomistic models of point defects into continuum thermo-chemical calculations, a model of oxygen diffusivity in $UO_{2+x}$ is developed and used to predict point defect concentrations, oxygen diffusivity, and fuel stoichiometry at various temperatures and oxygen pressures. The simulations of coupled heat transfer and species diffusion demonstrate that including the dependence of thermal conductivity and density on composition can lead to changes in the calculated centerline temperature and thermal expansion displacements that exceed 5%. A review of advanced nuclear fuel performance codes reveals that the many codes are too dedicated to specific fuel forms and make excessive use of empirical correlations in describing properties of materials. The paper ends with a review of international collaborations and a list of lessons learned that includes the importance of education in creating a large pool of experts to cover all necessary theoretical, experimental, and computational tasks.

The Effects of Family Structure on Children's Emotional and Behavioural Problems (가족 구조가 아동의 정서·행동 문제에 미치는 영향에 관한 일 연구)

  • Hwang, Hye Jung
    • Korean Journal of Child Studies
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    • v.15 no.2
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    • pp.195-211
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    • 1994
  • This study was designed to examine the effects of family structure (nuclear, extended family) on children's behavioral and emotional problems. The subjects of this study were 650 primary school children aged 8 to 13 living in Seoul and Incheon (324 from nuclear and 326 from extended families). The Children's Behaviour Questionnaire (CBQ: Rutter, 1970) and a questionnaire containing demographic questions and some additional questions were used for instruments. For the analyses, frequencies, descriptives, chi-square, factor analysis, and t-test were used. The results were analysed and explained in their cut-off points, prevalences, differences and factor structures. The cut-off score obtained in this study was 18, and the prevalences with this cut-off score were 6.3% in total subjects, 8.0% in nuclear families, and 4.6% in extended families. The children from extended families showed less behavioral and emotional problems, especially antisocial behaviours, compared with those from nuclear families, and this difference was significant (p<.05). The factor structures of the CBQ were 'antisocial', 'neurotic', 'mannerism' and 'speech' in total subjects, and, in the case of nuclear families, the factor structures were same as in total subjects, but, in the case of extended families, the 'emotional anxiety' factor was included instead of the 'speech' factor.

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Analysis of the Bacteria in Nuclear Medicine (핵의학 검사실내 세균 분석)

  • Shin, Seong-Gyu;Lee, Hyo-Yeong
    • Journal of the Korea Safety Management & Science
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    • v.19 no.2
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    • pp.95-100
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    • 2017
  • In this study, the bacterial contamination level of equipments and devices in the nuclear medicine department of a university hospital was investigated. CNS was detected from the sample collected from the door opening button of the nuclear medicine department. Bacillus sp. was detected from the table and CNS with Bacillus sp. were detected from the control button at the PET-CT room no.1. Also, CNS was detected from the table and the control button at the PET-CT room no.2. In the distribution room no.1, CNS and Bacillus sp. were detected while CNS being detected from the distribution room no.2 and CNS with Bacillus sp. being detected from the distribution room no.3. In the injection room, Enterrococcus faecium and Pontoea sp. were detected. On the table of the ecsomatics room, Pontoea sp. was detected. Bacillus sp. was detected from the inside of the syringe Pb shield and CNS was detected from the outside. Enterrococcus faecium was detected from the Gamma camera table and Bacillus sp. was detected from the door grip. On the chair at the patient waiting room, Pseudomonas aeruginosa abd Bacillus sp. were detected. Therefore, it was understood that infection should be prevented by securely sterilizing examination devices after each examination, maintaining cleanliness by regular sterilization of waiting chairs and such objects with a number of direct contacts with patients, and infection education for the features of nuclear department.

Removal of Cs+, Sr2+, and Co2+ Ions from the Mixture of Organics and Suspended Solids Aqueous Solutions by Zeolites

  • Fang, Xiang-Hong;Fang, Fang;Lu, Chun-Hai;Zheng, Lei
    • Nuclear Engineering and Technology
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    • v.49 no.3
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    • pp.556-561
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    • 2017
  • Serving as an excellent adsorbent and inorganic ion exchanger in the water purification field, zeolite 4A has in this work presented a strong capability for purifying radioactive waste, such as $Sr^{2+}$, $Cs^+$, and $Co^{2+}$ in water. During the processes of decontamination and decommissioning of suspended solids and organics in low-level radioactive wastewater, the purification performance of zeolite 4A has been studied. Under ambient temperature and neutral condition, zeolite 4A absorbed simulated radionuclides such as $Sr^{2+}$, $Cs^+$, and $Co^{2+}$ with an absorption rate of almost 90%. Additionally, in alkaline condition, the adsorption percentage even approached 98.7%. After conducting research on suspended solids and organics of zeolite 4A for the treatment of radionuclides, it was found that the suspended clay was conducive to absorption, whereas the absorption of organics in solution was determined by the species of radionuclides and organics. Therefore, zeolite 4A has considerable potential in the treatment of radioactive wastewater.

A Takagi-Sugeno fuzzy power-distribution method for a prototypical advanced reactor considering pump degradation

  • Yuan, Yue;Coble, Jamie
    • Nuclear Engineering and Technology
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    • v.49 no.5
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    • pp.905-913
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    • 2017
  • Advanced reactor designs often feature longer operating cycles between refueling and new concepts of operation beyond traditional baseload electricity production. Owing to this increased complexity, traditional proportional-integral control may not be sufficient across all potential operating regimes. The prototypical advanced reactor (PAR) design features two independent reactor modules, each connected to a single dedicated steam generator that feeds a common balance of plant for electricity generation and process heat applications. In the current research, the PAR is expected to operate in a load-following manner to produce electricity to meet grid demand over a 24-hour period. Over the operational lifetime of the PAR system, primary and intermediate sodium pumps are expected to degrade in performance. The independent operation of the two reactor modules in the PAR may allow the system to continue operating under degraded pump performance by shifting the power production between reactor modules in order to meet overall load demands. This paper proposes a Takagi-Sugeno (T-S) fuzzy logic-based power distribution system. Two T-S fuzzy power distribution controllers have been designed and tested. Simulation shows that the devised T-S fuzzy controllers provide improved performance over traditional controls during daily load-following operation under different levels of pump degradation.

Delta-form-based method of solving high order spatial discretization schemes for neutron transport

  • Zhou, Xiafeng;Zhong, Changming;Li, Fu
    • Nuclear Engineering and Technology
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    • v.53 no.7
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    • pp.2084-2094
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    • 2021
  • Delta-form-based methods for solving high order spatial discretization schemes are introduced into the reactor SN transport equation. Due to the nature of the delta-form, the final numerical accuracy only depends on the residuals on the right side of the discrete equations and have nothing to do with the parts on the left side. Therefore, various high order spatial discretization methods can be easily adopted for only the transport term on the right side of the discrete equations. Then the simplest step or other robust schemes can be adopted to discretize the increment on the left hand side to ensure the good iterative convergence. The delta-form framework makes the sweeping and iterative strategies of various high order spatial discretization methods be completely the same with those of the traditional SN codes, only by adding the residuals into the source terms. In this paper, the flux limiter method and weighted essentially non-oscillatory scheme are used for the verification purpose to only show the advantages of the introduction of delta-form-based solving methods and other high order spatial discretization methods can be also easily extended to solve the SN transport equations. Numerical solutions indicate the correctness and effectiveness of delta-form-based solving method.

The Ultrastructure of Spermatozoa of the Ussurian Bullhead, Leiocassis ussuriensis (Teleostei, Siluriformes, Bagridae) with Phylogenetic Considerations (대농갱이 Leiocassis ussuriensis 정자의 미세구조와 계통적 고찰 (경골어류, 메기목, 동자개과))

  • Kim, Kgu-Hwan;Lee, Young-Hwan
    • Korean Journal of Ecology and Environment
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    • v.33 no.4 s.92
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    • pp.405-412
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    • 2000
  • The fine structure of spermatozoa of Leiocassis ussuriensis was examined with scanning and transmission electron microscopies. The spermatozoon of L. ussuriensis is approximately $68.8\;{\mu}m$ in length and a relatively simple cell with a spherical nucleus, a short midpiece and a tail. The ultrastructure of spermatozoa of L. ussuriensis is characterized by the following features. The nuclear fossa, the length of which is about two-thirds of the nuclear diameter, contains two centrioles. The centrioles are orientated approximately $180^{\circ}$ to each other. The mitochondria are arranged in two layers and their number is 12 or more. The axoneme is the 9+2microtubular pattern and has inner but no outer dynein arms as in other bagrids. The two axonemal fins are in the same plane with the two central microtubules, the doublets 3 and 8. The axonemal fins and the inner dynein arm are shared in Bagridae and the deep nuclear fossa is shared in Siluriformes. The axonemal finsobse observed in Bagridae and Amblycipitidae of Siluriformes might be the apomorphic character in Ostariophysi. They are not reported in Cyprinidae and Characiformes.

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Apolipoprotein E Phenotypes and the Relationship Among Lipid Levels, Nutrient Intakes, Lifestyles and Risk Factors Between Subjects with and without Hyperlipidemic Risk (Apolipoprotein E 다형성과 고지혈증 위험 유무에 따른 혈중 지질농도, 영양소 섭취, 생활습관 및 위험요인과의 관계)

  • Lee, Jae-Eun;Cho, Sang-Woon;Kang, Ji-Yeon;Paek, Yun-Mi;Choi, Chang-Sun;Park, Yoo-Kyoung;Choi, Tae-In
    • Journal of Nutrition and Health
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    • v.41 no.5
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    • pp.402-413
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    • 2008
  • This study was performed to investigate Apolipoprotein E phenotypes and the relationship among lipid levels, nutrient intakes, lifestyles and risk factors between subjects with and without hyperlipidemic risk. The data were collected from 675 industrial male workers who had completed annual medical examination. Compared to the normal group, the hyperlipidemic risk group in Apo E3 and E4 had significantly higher BMI (p < 0.05) and showed significantly higher body fat (%), waist circumference and WHR in all types of Apo E (p < 0.05). In addition, the hyperlipidemic risk group had significantly higher total cholesterol, LDL-cholesterol, triglyceride and AI than the normal group in all types of Apo E (p < 0.05). Intakes of protein, calcium, phosphorus, iron, vitamin A, vitamin B1, vitamin B2, vitamin C and niacin in Apo E3 were significantly lower in the hyperlipidemic risk group than in the normal group (p < 0.05). In the logistic regression analysis, after adjustment for other factors, Apo E2 + E4, waist and WHR were the significant risk factors associated with hyperlipidemia, but protein intakes were associated with significantly lower risks of hyperlipidemia (p < 0.05). In conclusion, genetic factor (Apo E2 or Apo E4), anthropometric index and nutrient intake seem to influence hyperlidemic risk. Further studies and efforts will be needed to evaluate the independent relationships among hyperlipidemic risk factors.